|Information on: PV-Simulation for development and equipment testing|
|Further information with focus on SASControl software: SAS - PV-simulation|
In photovoltaic applications, the quality and technical data of the AC/DC converter is of primary interest. Solar installations are intended for a lifetime of roughly 20 years, so even fractional parts of a percent in efficiency will represent significant amounts of energy losses.
Development and final series testing of AC/DC converters call both for equipment able to simulate solar arrays of different type as close as possible to the original.
Manipulation of U/I – slopes: Cross-fading / dynamic behaviour
There are several factors causing variations of the basic slope values of a PV array:
Temporal progression of cloudiness
Temporal progression of temperature
Temporal progression of solar radiation geometry as a daily/annual variation
Partial shade caused by obstacles
Selective or integral degradation due to moist and pollution
Panel-failures, resistance of bonding and terminals
Most parts of the work to be done is reflected by the implementation of two physical units:
- changing the irradiance to a new reference value ( "setIrradianceRef(.....)")
- changing the temperature to a new reference value ( "setTemperatureRef(...)")
Tests based on normalized procedures
(e.g. EN 50530, Sandia Labs)
Normalized procedures are able to perform comparisons between different types of hardware and/or firmware. This in turn calls for highly precise data processing inside the simulator as also for stability and accuracy of the processes. This not only means precision of data, but also reproducible time-dependent actions.
As for our main customers, EN50530 is the most important standard to be implemented, we included the execution of those tests in the software. The corresponding scripts are provided as open source and free of charge. Thus the users are able to modify the test procedure to their own needs.
Of course other test procedures (like the tests defined by Sandia Labs) can be implemented and executed as SASControl provides an open environment.
The acronym „TopCon AAP“ stands for a standard TopCon DC power supply, functionally extended by the versatile software function generator TFE. This operation mode allows not only running time-dependent functional slopes, but also the famous ‘Application area-programming mode’. By this, arbitrary functions like the above stated solar cell slopes can be loaded, manipulated and displayed. Configured with an appropriate U/I-curve, TopCon behaves like a real solar cell array and allows therefore the simulation of nearly any configuration of cells.
|Power range||10/16/20/32 kW and multiples, e.g. n times 128 kW|
|Controller cycle time||20 kHz (= 50 µs)|
|Voltage range||Up to 1200 VDC, to 1500 VDC with series midpoint earthing|
|Resolution||12 Bit ( 0.025% F.S.)|
|Mains characteristics||3 x 400 VAC / 50/60 Hz; 3 x 480 VAC / 60 Hz for US|
|Temperature||0°C to 40°C; for degrading datasheet of respective unit type|
|AAP cycle time||20 kHz (= 50 µs)|
TopCon AAP with Post-processor unit TC.LIN
For the simulation of low-capacitance solar arrays in time-critical applications, REGATRON offers a Post-Processor unit TC.LIN as an extension to the above-described TopCon AAP system. This post-processing unit consists of an extremely fast current source fed by a full digital controller with a cycle time of only 5 usec! This unit enables the user to simulate low-capacity solar arrays with a phase error of only a fractional part of one electrical degree at a ripple frequency of 100 Hz.
TC.LIN communicates with the leading TopCon via the same proprietary CAN-bus, which is also being used for master-slave-operation. TopCon followed by a TC.LIN unit forms basically a primary switched DC power module with a second precision current controller. By this configuration, the advantages of both systems are combined to benefit from a high efficiency power conversion and a loss-optimized fast acting series controller.
|Power range||0-1500 V DC, 26/13 ADC current ranges to 50/25 ADC|
|Controller cycle time||5 µs ; resolution 14.5 bit ; ( 4.3 * 10E-05)|
|Controller voltage reserve||programmable , Udrop = 30 ... 50 Volt is suggested|
|Power losses||1.5 kW permanent, up to 3.0 kW temporary, air cooling|
|Error handling||Overvoltage; overcurrent, SOA-limit surveillance, supply voltages, internal processor/bus errors|
|Cabinet||Rack 19“, 6 HU|
Further Information on the TC.LIN post-processing unit.
Note: Both ‚TopCon AAP’ as also the combination ‚TopCon/TC.LIN’ can easily be controlled and parameterised by standard TopControl software. This software is provided with each TopCon delivery and is working through RS232 or alternatively USB interface.
Significant more functionality with a view to SOLAR applications is provided by the new software package SAScontrol. This software allows for the implementation of all functional demands raised in the previous chapters .